refactor: deprecate FAPI 1.0 ID2, lax request objects, plain PKCE

lib/helpers/configuration.js

@@ -1,3 +1,5 @@
+import { deprecate } from 'node:util';
+
 import { JWA } from '../consts/index.js';
 
 import get from './_/get.js';
@@ -24,6 +26,21 @@ function filterHS(alg) {
   return alg.startsWith('HS');
 }
 
+const deprecations = {
+  lax: deprecate(
+    () => {},
+    'The "lax" Request Object mode is deprecated and will be removed in the next major revision.',
+  ),
+  ID2: deprecate(
+    () => {},
+    'The "1.0 ID2" FAPI Profile is deprecated and will be removed in the next major revision.',
+  ),
+  plain: deprecate(
+    () => {},
+    'The "plain" PKCE method is deprecated and will be removed in the next major revision.',
+  ),
+};
+
 const filterAsymmetricSig = RegExp.prototype.test.bind(/^(?:PS(?:256|384|512)|RS(?:256|384|512)|ES(?:256K?|384|512)|EdDSA)$/);
 
 const supportedResponseTypes = new Set(['none', 'code', 'id_token', 'token']);
@@ -341,6 +358,9 @@ class Configuration {
       if (!['plain', 'S256'].includes(type)) {
         throw new TypeError('only plain and S256 code challenge methods are supported');
       }
+      if (type === 'plain') {
+        deprecations.plain();
+      }
     });
   }
 
@@ -397,6 +417,10 @@ class Configuration {
     if (!requestObjectStrategies.has(this.features.requestObjects.mode)) {
       throw new TypeError(`'mode' must be ${formatters.formatList([...requestObjectStrategies], { type: 'disjunction' })}`);
     }
+
+    if (this.features.requestObjects.mode === 'lax') {
+      deprecations.lax();
+    }
   }
 
   checkFapiProfile() {
@@ -409,12 +433,18 @@ class Configuration {
         if (profile && !fapiProfiles.has(profile)) {
           throw new TypeError(`'profile' must be ${formatters.formatList([...fapiProfiles], { type: 'disjunction' })}`);
         }
+        if (profile === '1.0 ID2') {
+          deprecations.ID2();
+        }
         return profile || undefined;
       };
     } else if (!fapiProfiles.has(this.features.fapi.profile)) {
       throw new TypeError(`'profile' must be ${formatters.formatList([...fapiProfiles], { type: 'disjunction' })}`);
     } else {
       const value = this.features.fapi.profile;
+      if (value === '1.0 ID2') {
+        deprecations.ID2();
+      }
       this.features.fapi.profile = () => value;
     }
   }